[comp.sys.atari.st.tech] Mega2 to Mega4 upgrade?

freds@hpspdra.spd.HP.COM (Fred Saavedra) (05/21/91)

I have a MEGA 2, would like to add more RAM to 4 meg.

Can I just solder the new memory chips in place? Do I have
to do anything else?

I have a good ESD safe workarea and a great vacuum desoldering
tool. So solder removal is not a problem. 

I have the latest Rainbow TOS installed. I put it in last month.

thx 

freds@hpspdra.hp.com

whitcomb@aurs01.UUCP (Jonathan Whitcomb) (05/22/91)

In article <24150001@hpspdra.spd.HP.COM> freds@hpspdra.spd.HP.COM (Fred Saavedra) writes:
>I have a MEGA 2, would like to add more RAM to 4 meg.

Good plan!  After I did it I couldn't believe I had waited so long.

>Can I just solder the new memory chips in place? Do I have
>to do anything else?

First you have to make sure that your motherboard does indeed have the
holes in the circuit board for the extra memory (apparently about
10% of the boards do not).  If so, you're all set.  Atari filled all
of the holes with solder (either out of malice or just lazy wave-
soldering), so you'll have to suck the solder out of 300+ holes
before you can do anything else.  That's what took me the most time.

Basically, all you NEED are 16 RAM chips and three 33 ohm resitors.
It's not a bad idea to use sockets for the chips, and 16 .1 uF
capacitors as well.  There are holes in the circuit board for
the capacitors and resistors.

>I have a good ESD safe workarea and a great vacuum desoldering
>tool. So solder removal is not a problem. 

Good!  You'll have an easier time of it than I did.  

For those of you that don't have an ESD safe work area, you might
check out the sidebar article in April's Atari Informer... I used
these tips when I did my work.

I performed this operation last month with great results.  I ordered the
parts from D&P Computer (800-535-4290), and they sent me a printout
of a GEnie file that had instructions.  They also sent along an Atari
User magazine... nice guys.

The GEnie instructions had good tips for avoiding ESD, cleaning off
the flux, and periodic sanity checks.  If someone has GEnie access,
I hope you'll post these to the archives.

Good luck!
**********************************************************************
Jonathan Whitcomb                    UUCP: <whitcomb%aurgate@mcnc.org>
Alcatel Network Systems, Raleigh, NC                    Delphi: JBWHIT